1. Field of the Invention
The present invention relates to a display device including an organic electroluminescent element and a manufacturing method thereof, and more particularly to a barrier film that blocks transmission of a substance degrading the organic electroluminescent element.
2. Description of the Related Art
A flat panel display such as an organic electroluminescent (EL) display device includes a display panel including thin film transistors (TFTs) or organic light-emitting diodes (OLEDs) as organic electroluminescent elements formed on a substrate. Heretofore, a glass substrate has been used for the substrate of the display panel. In recent years, however, a flexible display is being developed in which polyimide as a resin film is used for the material of the substrate so that the display panel can be bent.
A protective film that protects the OLED whose characteristics are degraded by moisture or the like is provided in the organic EL display device. For example, the organic EL display device has a structure in which an element substrate on which the OLEDs and the like are formed and a counter substrate on which color filters and the like are formed are bonded together with a filling resin layer interposed therebetween. A sealing film having a moisture-proof function to protect the OLEDs against moisture contained in the filling layer is formed on the OLEDs. Moreover, in order to prevent entry of moisture from a polyimide film serving as a base material of the element substrate, a barrier film with low moisture permeability is provided between the polyimide film and the OLEDs. As the barrier film, a silicon oxide film or silicon nitride film that is stacked by a chemical vapor deposition (CVD) method, or an organic film that is deposited by a vapor deposition method is used.